Projection printer lens



United States Patent O 3,320,017 PROJECTION PRINTER LENS v Willy E. Schade, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation f New Jersey Filed Mar. 26, 1963, Ser. No. 268,012 3 Claims. (Cl. S50- 222) -tween two positive elements.

The object of Vthe present invention is to provide a fairly high aperture lens, up to f/4.5 covering a relatively wide field and with low distortion, low lateral color, low coma, and low rim ray discrepancy. That is, the object of the invention is to provide a lens with high resolution out to the edges of a wide at field.

The basic six-element lens of this general type has ten optical surfaces which are spherical or plano, surfaces 4 and 7 being cemented. The present invention can be described with reference to the curvatures of the surfaces. The outer components, namely elements 1 and 6, are preferably of highindex of refraction, and the other four elements are preferably of average index of refraction between 1.55 and 1.60. The elements adjacent to the central airspace are negative elements with a dispersive index V between 40 and 45, which is somewhat larger V value than is normally used in this type of lens.

There is nothing unusual about the axial thicknesses of the elements and the spacings thereof, but to obtain the high correction mentioned above, they must be held within certain limits. Also the front surface of the front doublet and the rear surface of the rear doublet have radii of lcurvatures similar to most lenses of this type. The distinctive features of the present lens lie primarily in the curvatures of the surfaces of the outer components and in the curvature of the cemented surfaces and surfaces adjacent to the central airspace.

The high degree of correction is obtained according to` the present invention when the values of the index of refraction ND, lthe dispersive index V, the surface radii R, the thicknesses t and the spacings s have values within the following ranges', the elements and surfaces being numbered from the long conjugate side herein referred to as lthe front, and and radii referring respectively to surfaces convex and concave to the front. F is the focal length of the lens. The lens when used in projection printing normally works from a magnification of 1:1 (in which case the conjugates are equal) up to a magnification of 5:1, 10:1, or even larger, in which case there is definitely a long conjugate .and a short conjugate side.- This does not mean that the lens cannot be focused down to give satisfactory prints at slightly less thaJn 1:1," but the term long conjugate side or front refers to the direction in which the long conjugate side of the lens is facing when it is used at say 6: l magnification.

l to operate at magnifications from 1:1 to 8.5: l. This lens 3,320,017 Patented May 16, 1967 ICC It will be noted that the ranges for R1, R4, R5, R8 and R10 are somewhat restricted compared to the ranges for R2, R7 and R9.

In the accompanying drawing:

FIG. 1 illustrates a cross section of a preferred embodiment of the invention.V

FIG. 2 gives the specification for that embodiment which corresponds to Example 3 below.

Three examples of preferred embodiments of the invention are as follows:

Example `1 The following is the specification of a lens designed to operate with high resolution at magnifications from 1:1

to 6: l.

F mm. f/4.5

Lens N., V Rndii, mm. lhicknesses,

1. 745 45. 6 Rx +382 I il =4.5

R2 -I-14L4 si= 1.8 l. 573 56. 8 R3 +45.0 II tz=4.9

l. 573 42. 5 R4 41.3 III a= 1.9

32=6.4 1. 573 42. 5 Ri -2a.4 a

it=1.9 1. 573 56. 8 RJ =+41.3

1. 745 45. R9 141.4 VI ta=4.5

Rio= -382 Y B F=s4.1

Example 2 ,The following is the specificationof a lens also de signed to operate at a magnification kof 1:1 to 6:1 with somewhat better correction for rim raysthan Example 1.

' F=1oo mm. f/4.5

Lens N V Radii, mm. Thicknesses,

inni.

1. 745 45. 8 R1 +35. 7 I t1 =4. 6

Si =1. 7 l. 573 56. 8 R3 =+43. 0 H z2=4.8

1. 573 42. 5 R4 33. 7 III 2a=1. 9

R5= +22. 6 g 8z=10. 2 1. 573 42. 5 Re =-22. 6 IV t4=1. 9

1. 573 56. S R1 +61. 0 V 5=4. 7

Rg=38. 3 83=1. 7 1. 745 45. 8 Re 124. 2 V1 la=4. 3

R|u=39. l BF=S0. 7

Example 3 The following is the specification for a lens intended has even better correction Yfor rim ray than Example 2 spacing of the elements all numbered by subscripts from above. Y front to rear and F is the focal length of the lens:

F=100 mm. !/4.5

l Lens Nn V Radii Tliicknesscs Lens N i, V Radii, mm. Thicknesses, 5

. nlm.

1. 75 46 R1 =+.36 F 1. 745 45.8 Ri =+35. 7 I R2 :H w F' ='05 F I t1=4-5 .51:92 F

R1 =+1100 81:1 7 H 1.57 57 Ra =+.43 F 1.573 55.8 R3==+431 '7 n L 57 43 R4 34 F t2=05 F l7=49 III 3: 02 F 1.573 42. 5 R4 =337 R5 :+23 F 3=L9 31=.10 F R5=+22. 7 v 1. 57 43 Ri =-.23 F

52=10-2 IV 4=,02 F 1.573 42.5 R6 =22.3 1 57 57 R1 61 F IV t4=19 V 5: 05 F 1. 57a 55.5 R1=+63.o Ra 38 F V s=47 3: 02 F R8 ='37' 6 53:1 7 VI 1.75 46 Ri =-1.24 F t 04 F 1.745 45.8 R =-iis.s v1 =4 3 R10" '39 R10=33. 4 s

BFzgl'o 3. A lens having substantially the following specifical tions, where ND is the index of refraction and V is thev I claim: dispersive index of the elements, R is the radius of curva- 1- A lens havlpg Subtant1auy the follOWmg SPelCa ture of the surfaces, t is the axial thickness and s is the UPUS [Vhehfe ND 1S the Index 0f refraction nd V 1S the 25 spacing of the elements all numbered by subscripts from dispersive index of the elements, R is the radius of curvafrom to rear and F is the focal length of the lens; ture of the surfaces, t is the axial thickness and s is the spacing of the elements all numbered by subscripts from Lens N v Rad Thicknesscs front to rear and F is the focal length of the lens: n

, 3o Lens Nn V Radll Thicknesses 1.75 46 Ri =+-36 F `I ,=.o5 F R7 =+1.10 F 02 F R F s I 1 75 46 l +38 z,=.05 F 1.57 57 R, =|.43 F

R1 =-l-1. 41 F II v g,= 05 F 02 F *35 HI 1.57 43 R4 =.3l F t 02 F 1.57 57 R =+.45 F 3= u 57 43 R 41 F v R =+23 F 8 10 F z= 1n 1' v 1.57 4a R, =.22 F t 02 F R :+23 F V1.57 57 R1=+.63 F Iv 1. 57 4a R5 =-.23 F R 38 F z5=.05 F

s 4 .i ='.02 F v 1 57 57 R l F 1.75 4e R, =1.17 F t3 04 F R =-.45 F E R,=-.aa F v 1.75 4e R =-1.41F VI Rio=.38 F l No references cited.

2. A lens having substantially the following specifications, where ND is the index of refraction and V is the dispersive index of the elements, R is the radius of curvature of the surfaces, t is the axial thickness and sis the 

1.75 46 R1 =+38 F I---------- T1=.05 F R2 =+1.41 F S1=.02 F 1.57 57 R3 =+.45 F II--------- T2=.05 F 1.57 43 R4 =-.41 F III-------- T3=.02 F R5 =+.23 F S2=.06 F 1.57 43 R6 =-.23 F IV--------- T4=.02 F 1.57 57 R7 =+.41 F V---------- T5=.05 F R8 =-.45F S3=.02 F 1.75 46 R9 =-1.41F VI--------- T6=.05 F R10=-.38 F
 1. A LENS HAVING SUBSTANTIALLY THE FOLLOWING SPECIFICATIONS, WHERE ND IS THE INDEX OF REFRACTION AND V IS THE DISPERSIVE INDEX OF THE ELEMENTS, R IS THE RADIUS OF CURVATURE OF THE SURFACES, T IS THE AXIAL THICKNESS AND S IS THE SPACING OF THE ELEMENTS ALL NUMBERED BY SUBSCRIPTS FROM FRONT TO REAR AND F IS THE FOCAL LENGTH OF THE LENS: 